Document processing devices include printers, copiers, scanners and e-mail gateways. More recently, devices employing two or more of these functions are found in office environments. These devices are referred to as multifunction peripherals (MFPs) or multifunction devices (MFDs). As used herein, MFP means any of the forgoing.
An electrostatic process unit (EPU) in many toner-based printers and multifunction peripherals performs the printing function. The EPU typically comprises a photoconductive drum, a developer roller, and a charge unit among other components as would be known in the art. Using magnetic and electrostatic forces, the developer roller and the photoconductive drum transfer toner from an associated toner hopper to a sheet of paper where it is fused by heat to the paper. After the photoconductive drum transfers toner to the paper, a cleaner blade in the EPU removes residual toner and paper dust from the photoconductive drum.
During printer startup operations, uncharged sections of the photoconductive drum can attract toner from the developer roller. This unintentionally transferred toner is outside the print area and is removed as waste toner from the photoconductive drum and discarded. In many instances, the amount of waste toner can exceed the total amount of toner deposited on a typical 2 page print job.